var result = 0

for (var i = 2; i < process.argv.length; i++)
    result += Number(process.argv[i])

console.log(result)

// Also be aware that all elements of process.argv are strings and you may
// need to coerce them into numbers. You can do this by prefixing the
// property with + or passing it to Number(). e.g. +process.argv[2] or
// Number(process.argv[2]).
